It’s day one of the U.S. Open Tennis Championships, held at Flushing Meadows-Corona Park. For urban explorers, the park has long held a special lore, with its layered history and abandoned structures. As you’ll see in this collection of secrets, its past and proposed future continue to reflect the push and pull of New York City development and most spectacularly its hidden spots may reveal themselves in centuries to come, or never again.

10. Flushing Meadows-Corona Park Has A Buried Time Capsule To Be Opened in the Year 6939

The device was an engineering feat, a “time capsule” as notable New York public relations counselor George Edward Pendray called it for the very first time in 1939. We’ll just have to wait another 4900+ years to see it again.